also use logging module output with --debug
use logger for debug output
use logger for print_error
only log INFO to console, DEBUG to file
different logger for backends
prepend ERROR also without --debug
start logging before option parsing

Additionally log some version informations as INFO,
rather than printing it.
windows: use libdiscid drive detection if available

libdiscid >= 0.6.0 can detect which drive letter
is the first cd drive. So we want to use that,
rather than just using D: as a default.
Merge branch 'logging'

see pull request #87
Merge branch 'w32_drive'

see pull request #86

Conflicts:
	isrcsubmit.py